Well, let's take a moment to appreciate the beauty of subtraction here. When we subtract 500 from 900, we're left with 400. Just imagine that as a happy little number finding its place in the world. Remember, there are no mistakes in math, just happy little accidents.

Oh, dude, like, 900 minus 500 is, like, 400. So, if you had 900 cookies and you ate 500 of them, you'd have 400 left. But, like, who's counting when there are cookies involved, am I right?

The difference between 900 and 500 is 400. This is calculated by subtracting 500 from 900, which results in 400. Mathematically, the calculation is represented as 900 - 500 = 400.